It's worth noting that Facebook has a separate recruiting team for higher-level hires, starting at either IC5 or (more likely) IC6. In any case I know because it included me. From what I can tell, hiring at IC7 and above is so hard that the process for most candidates deviates in some way from what's usually described. I saw some really great hires (that might otherwise not have happened) that way, and some that were ... less great. Basically it increases the variance that the standard process is constructed to minimize at lower grades.

I have heard similar comments from multiple FAANG employees.